Acoustical apparatus



March 12, 1940. FISHER 2,193,398

ACOUSTICAL APPARATUS Filed Dec. 11; 1937 Patented Mar. 12, 1940 UNITED STATES.

PATENT OFFlCE 8 Claims.

This invention relates to acoustical apparatus and more particularly to a loud speaker for use in connection with sound reproduction.

Acoustical devices for the reproduction of sound and loud speakers in use today fail to present proper tonal effects in that essential resonating'features have not been incorporated in their design. Previous to my invention, manufacturers have been reluctant to provide proper resonating means, baffles, sounding board, and flare members because of lack of space in a cabinet of reasonable size with known arrangements parts. I

Some manufacturers of radio sets today are so designing their speakers in relation to the remainder of the apparatus that when sound emanates therefrom more or less objectionable resonance tones accompany the sound reproduction.

It is an object of my invention to provide a loud speaker having pleasing tonal qualities and resonating features of compact form.

It is afurther object of the invention to provide. sound reproducing apparatus with an arrangement whereby resonance emanating therefrom may be controlled by the listener or operator. y

Other objects and the nature and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a front elevation of sound reproducing apparatus with parts cut away disclosing a loud speaker in accordance with the invention; 7

-Fig. 2 is a section taken along line 2-2 of Fig. l; and,

Fig, 3 is a fragmentary section taken along line 33 of Fig. 2 looking in the direction of the arrows disclosing the mechanism for controlling resonance.

Referringto the drawing, cabinet [0 is arranged to house a sound reproducing apparatus in the upper portion thereof which may take the form of a radio set II having a volume control and switch knob [2, a tuning control knob l3; tuning dial l4, and resonance control knob 45. In the lower portion of the cabinet an inclined sounding board 16 may be arranged having secured thereto by any suitable means a conventional loud speaker IT. A flare member l8 which may take the form of a hollow frustrated cone is secured to the rear portion of the sounding board and the outlet of the speaker. The sounding board I 6 has arranged thereon and therethrough a desirednumber of resonating tubes I9, I have shown twelve in Fig. 3, for attributing to the device proper pleasing tonal effects. The tubes l9 are arranged on thesounding board H3 in a manner such that their axes are perpendicular to the sounding board and in line with the loud speaker H, the axis of which is also perpendicular to the sounding board and further in a manner such that the front faces 26 of the tubes if; he in a plane parallel to the front of the cabinet and. intersectsaid plane to form ellipses as shown in Fig. 1. To effect this arrangement the shorter 10 tubes are placed'near the bottom of the sounding board it which is inclined in a manner whereby its bottom portion is relatively close to the front of the cabinet, .its top portion is relatively far from the front of the cabinet, and the succeeding longer tubes are arranged higher up on the sounding board 18 as shown on the drawing. In addition to the tubes i9 that transmit the tone from the front of the speaker, another set of tubes 2| maybe arranged in circular form about the tubes 19 and through the sounding board It in communication with the space between flare member 18 1 and housing 22 which envelops speaker H but is arranged in spaced relation thereto and secured to sounding board 16 in a manner to include the portions or" the tubes 2i arranged in the sounding board whereby the tubes 2i may carry sound that originates from the rear of the speaker, which involves more or less objectionable resonance tones, and is sometimes 0 desirable and at other times undesirable. The housing 22 may be fabricated of sound deadening material such as felt paper, for example.

In practice Ihave found that the sound that emanates from the speaker is weaker at or near its-circumference and to compensate for this weakness tubes 2! have been provided to bring additional volume from the rear of the speaker which more or'less equalizes the sound emanating from substantially the entire area of the sounding board. Should this added sound be too great forthe room or listener, I may provide a con-' trol, comprising knob l5 cooperatively associated with shaft 23 in a. manner whereby through worm and gear mechanism 24, the shaft 25 may rotate pulley 26 winding thereon Wire 21 which is attached to rotate at annular disc 23, at car 29, causing said annular disc to rotate in the direction of the arrow as shown in Fig. 3. Tending to pull rotating annular clisc back to its original position is spring 36 fixed to a portion of the cabinet by hook -3| at one end and at its other end fastened to wire 32 which engages ear 33 of the rotating disc 28. Guide means- 34 may be provided in cooperative relation to rotating disc 28 whereby circular openings 35 arranged said annular disc to correspond with the openings in tubes ill may transmit all, part or substantially prevent the transmission of sound from the rear of the speaker, through tubes 2! to the listener, dependin on the position of the annular disc 28 which in turn is controlled by the knob l5.

On the front of the sounding board complete- 1y housing the resonating tubes l9 and the tubes ii a. housing 36 may be provided with a substantially circular cross section at its base 31, and an inwardly curved portion at its front end 38. The housing 35 may be fabricated of a sound deadening material such as paper or the like. With this arrangement sound emanating from the resonating tubes will be concentrated and prevented from spreading over a wide area thereby giving warmth to the sound reproduction which is noticeably pleasant. The housing 36 is similar in design to the shape formed by a singers lips to concentrate the sound emanating from his mouth and which gives a mellow effect thereto.

With the arrangement described, sound may be reproduced in a pleasing and effective manner with the absence of harsh vibrant effects, with a control of resonance and in a greater volume without distortion. Frequently, a listener to or operator of a radio set, as manufactured today, will be unable to satisfactorily hear the tones of the various instruments of the original composition unless the volume control is turned up to a point where it is no longer pleasing, because of the accompanying excess noise or volume. With my invention, however, it is possible to reduce the size of the speaker proper and still receive the desired tonal effects which makes it feasible to produce a console at lower cost without aifecting the quality of reproduction.

It will be obvious to those skilled in the art that various changes may be made in this device without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawing and described in the specification but only as indicated in the appended claims.

I claim:

1. An acoustical device of the class described including a cabinet having a generally vertical front wall, a sounding board in said cabinet tilted rearwardly at its upper portion, sound producing means arranged on one side of said sounding board, the axis of said sound producing means being generally normal to said sounding board, resonating tubes arranged on the opposite side of said sounding board, said resonating tubes being of varying sizes and arranged I in a manner whereby the edges of said resonating tubes furtherest from said sounding board lie in a substantially vertical plane, the longer resonating tubes being arranged relatively remote from the bottom of the board and the shorter tubes being arranged relatively remote from the top of the board, whereby a minimum of space is occupied by the sounding board and tube construction.

2. An acoustical device of the class described including a cabinet having a generally vertical front wail, a sounding board in said cabinet tilted rearwardly at its upper portion, sound producing means arranged on one side of the sounding board, the axis of said sound producing means being generally normal to said sounding board, a housing within said cabinet in spaced relation to said sound producing means and cooperating with said sounding board to envelop said sound producing means, openings in said sounding board communicating with the space between said sound producing means and the housing therefor, and valve means cooperating with said openings.

3. The structure recited in claim 2, said valve means being manually adjustable.

4. An acoustical device of the class described including a cabinet having a generally vertical front wall, a sounding board in said cabinet tilted rearwardly at its upper portion, sound producing means arranged on one side of said sounding board, the axis of said sounding producing means being generally normal to said sound producing means, resonating tubes arranged on the opposite side of said sounding board, said resonating tubes being of various sizes and arranged in a manner whereby the edges of the resonating tubes furtherest from the sounding board lie in a substantially vertical plane, the longer resonating tubes being arranged relatively remote from the bottom of the board and the shorter tubes being arranged relatively remote from the top of the board, a housing in spaced relation to said sound producing means and cooperating with said sounding board to envelop said sound producing means, said sounding board being formed with openings communicating with the space between said sound producing means and the housing therefor, and valve means cooperating with said openings.

5. The structure recited in claim 4, said valve means being manually adjustable.

6. An acoustical device of the class described comprising a sounding board, sound producing means ar-anged on one side of said sounding board, the axis of said sound producing means being generally normal to the plane of said sounding board, resonating tubes arranged on the other side of said sounding board, generally tubular sound concentrating means partially enveloping said tubes, said concentrating means having an annular inturned portion, said. concentrating means cooperating with said sounding board to effect a pleasant and intimate tonal quality.

7. An acoustical device of the class described comprising an inclined sounding board, sound producing means arranged on one side of said sounding board and generally normal to its plane, resonating tubes arranged on the other side of the sounding board and also generally normal to its plane, sound concentrating means partially substantially cylindrical and partially annularly converging, said sound concentrating means partially enveloping said tubes and cooperating with said sounding board to effect a pleasant and intimate tonal quality.

8. An acoustical device of the class described comprising an inclined sounding board, a sound producing means arranged in operative relation to said sounding board, resonating tubes arranged on said sounding board, said tubes and said sound producing means having generally parallel axes, said resonating tubes being of various sizes and arranged in a manner whereby the edges of said resonating tubes furtherest from said sounding board lie in a substantially vertical plane, said inclined sounding board extending rearwardly at its upper portion, whereby a minimum of space is occupied.

ALLAN W. FISHER. 

